Many work lamps, dive lamps,
and other lamps originally designed around the relatively inefficient
automotive 9005 (HB3) or 9006 (HB4) headlamp bulbs can be significantly
upgraded by retrofitting the newer 9011 (HIR1) and 9012 (HIR2) headlamp
bulbs. The
9011 and 9012 have the same filament geometry and
placement as the
9005 and 9006, and draw the same amount of electric
current—they are not high-wattage bulbs; there's no
extra power draw to endanger wiring or extra heat output to
threaten plastic lamp components—but they have much
greater luminous efficacy (lumens per watt) by design, so they produce
much more light.

When making this bulb swap,
use only a 9011 in place of a 9005, and only a 9012 in place of a 9006.
One of the three plastic base tabs of an HIR bulb must be slightly trimmed
with a small saw, a file, or a Dremel tool to fit in place of a non-HIR
bulb. The diagram below shows how to do so.

Fit problems are quite rare, but occasionally you may encounter a lamp
into which the HIR bulb will not quite fit, either because of a casting
ridge on the inside of the round hole through which the bulb shank
protrudes into the lamp, or because the bulb base tabs are slightly too
thick to rotate into position in the lamp's bulb seat.

In the first
case, the casting ridge can easily be removed by wrapping a strip of
100-grit sandpaper around your finger, abrasive side out, and going round
and round the bulb shank hole with your abrasive-wrapped finger until the
ridge has been smoothed away. Use a damp paper towel to wipe the inside of
the shank hole to remove the sanding dust, and then the bulb will fit
right in.

In the second case, usually bevelling the leading rear edge of
each bulb base tab with a file, dremel tool or sandpaper will allow it to
twist securely into the bulb seat. Some lamps have bulb seats that can be
adjusted for bulb base tabs of various thickness, because the seat is held
to the rear of the lamp with screws. Simply loosen the screws slightly
until the thicker base tab is accommodated.

But in most cases, there'll
be no such fit problems once you trim the top tab according to the image
below.